1. Field of the Invention
The invention relates to a processing system for a wiring harness, a method for testing electrical connection of a wiring harness, a computer-readable storage medium storing a computer program and a wire connection assisting system.
2. Description of the Related Art
A wiring harness is an electrical wiring system that forms a complicated network, and an electrical connection test is conducted during its production process to determine whether the constructed network is satisfactory.
Processing systems for wiring harnesses are disclosed in Japanese Unexamined Patent Publications Nos. 6-258371 and 10-132885 and Japanese Unexamined Utility Model Publication No. 6-72066. These known systems have a master unit with an electrical connection testing function and connector units to be connected with the wiring harness to enable a multiplexing communication.
In such a prior art, the wiring harness and the master unit are electrically connected via adapters provided between the wiring harness and the connector units. The multiplexing communication between the master unit and the connector unit is conducted by a so-called CSMA/CD (carrier sense multiple access with collision detection) method, and xe2x80x9csurvival arbitrationxe2x80x9d is adopted in the case that data are simultaneously outputted from a plurality of units for making a judgment based on bit lengths of two signals. The respective connector units are provided with a microprocessor to enable such a communication control and electrical connection tests.
A demand has existed in recent years to test an electrical connection of the wiring harness every time a harness-forming wire is connected during the production of the wiring harness. In this regard, a harness-forming wire is a subassembly of a wiring harness, and may be a wire cut to a specified length and having terminals connected with the opposite ends or a subassembly connected with connector(s). An electrical connection test must be conducted in real time every time an operator connects the harness-forming wire.
The survival arbitration based on the CSMA/CD method has been adopted as a communication method for electrical connection tests conducted by the above testing device. Thus, communication conditions must be established between the master unit and the connector units. Further, there is a waiting time when there is a collision of the signals. Accordingly, a response time between the end of the connecting operation and the end of the electrical connection test becomes longer, and the operator must wait longer. Therefore, the above communication method was not practical.
An attempt could be made to process the signals from the master unit and the connector units by a method other than the multiplexing communication. However, signal lines for the electrical connection test cannot physically be laid on an assembling board, and it is impossible to perform connecting operations on a compact assembling board for the large wiring harnesses that have been demanded in recent years.
More and more electronic equipment is being installed in vehicles, and wiring harnesses for the vehicles are getting larger and have complicated branch wires. Thus, wiring harnesses generally are produced by dividing the wiring harness into several subassemblies that are assembled into the wiring harness on a wire laying board.
A wire connection assisting system is known for carrying out the above-described assembly method. The system has a plurality of wire supplies for accommodating wires that have been cut to specified lengths. Terminals are connected with the opposite ends of the insulated wires in the wire supplies, and the terminated wires are sorted according to type. The terminated wires taken from the wire supplies are connected on assembling boards. More particularly, connector holders extend from the assembling boards and are adapted to hold connectors that are to be connected with the terminal-provided wires taken from the wire supplies. A wire connection instructing mechanism for identifying the wires that are to be connected with contacts of the connectors held in the respective connector holders.
The number of circuits of the subassembly to be formed has been increased (e.g. 200 to 300 circuits or 960 points or contacts) in recent years. Accordingly, there has been a demand to distribute the wire supplies to a plurality of stations and to convey the assembling boards from upstream stations to downstream stations. Wire connection instruction means need to be distributed to the stations as the wire supplies are distributed, and the wire connection instruction means at the respective stations need to identify a wire connection in cooperation with detecting elements of the connector holders.
To realize such cooperation, a master unit has been provided for each wire supply and is connected with the respective detecting elements of the connector holders via an interface connector on the assembling board. However, in such a case, it is cumbersome to connect and disconnect the interface connector, and poor operability results.
A mixed production produces many kinds of wiring harnesses in the same conveyor line. For these situations, it has been necessary to input pieces of production information of the respective wiring harnesses in all the master units at the respective wire supplies and to renew these pieces of information. Thus, a considerable amount of operation has been necessary to prepare for the mixed production.
The master units are at the wire supplies. Thus, a problem, such as a defective product, on any assembling board adversely affects the connecting operations on the other assembling boards unless problem information is transmitted to the respective master units. Accordingly, a system for enabling communication between the master units has been required.
It would be desirable to provide the master unit on the assembling board and to enable information of a single database built in this master unit to be shared by the respective connection instructing means. However, it has been necessary to establish a protocol between the master unit and the respective connection instructing means in a general multiplexing communication system. Thus, it has taken time to transmit data and, a problem of being incapable of executing practical controls has been unavoidable.
In view of the problems in the prior art, an object of the present invention is to improve operability of producing wiring harnesses by enabling electrical connection tests to be performed within a practical response time when the electrical connection test is conducted substantially every time a harness-forming wire is connected on a compact assembling board and by allowing easy, precise and continuous operations of connecting wires of a wiring harness to form a large-scale circuitry on the same assembling board.
The invention is directed to a processing system for a wiring harness in a production line for producing the wiring harness by conveying a connection board from one to another of a plurality of stations and connecting harness-forming wires to form the wiring harness on the connection board. The processing system functions to test an electrical connection at least part of a network of the wiring harness, including the connected harness-forming wire, substantially every time the harness-forming wire is connected. The system comprises a master unit for conducting an electrical connection test for the wiring harness being produced. The processing system also comprises connector units that are connected at least temporarily with the master unit to enable a multiplexing communication. The connector units also can exchange signals with at least part of the wiring harness. The processing system also comprises a multiplexing communication path for connecting the master unit and the respective connector units to enable the multiplexing communication therebetween. Different node addresses are set for the master unit and the respective connector units. Each of the master unit and the connector units comprises a multiplexing communication controller that adopts a perfect time-division multiplexing communication method according to which tokens are given to the master unit and the connector units by a time-division technique based on timing bit sets issued at specified intervals from any of the units and the node addresses. The master unit preferably has read data storage means for storing connection information of the network formed by the newly connected harness-forming wire as read data based on a data packet sent from the connector unit via the multiplexing communication with the connector unit by the perfect time-division multiplexing communication method. The master unit also has test standard data storage means for storing test standard data as a standard of the electrical connection test. The master unit also preferably has a discriminating means for discriminating whether contacts of the network are connected properly by comparing the read data and the test standard data. The test standard data storage means stores electrical connection test information of the network built by the harness-forming wires as the test standard data up to a final stage for each harness-forming wire, and the discriminating means discriminates whether the network is satisfactory up to the last stage based on the test standard data every time the harness-forming wire is connected in the production process of the wiring harness being tested.
Accordingly, the tokens are given to the respective units by the time-division technique based on the timing bit sets issued at the specified intervals from any of the units and the node addresses. Electrical connection of the network is tested every time a harness-forming wire is connected as an element of the wiring harness on the connection board being conveyed from one to another of the plurality of stations. Thus, it is not necessary to establish communication conditions between the units, and the data can be transmitted and received between the units without a protocol, thus improving operability. Therefore, an elapsed response time between the end of the electrical connection test and the end of the operation of the connecting the harness-forming wire can be shortened remarkably, and the next connecting operation can follow without making an operator wait.
It is unnecessary to establish communication conditions between the master unit and the connector units. Thus, each connector unit need not have a microprocessor, and a simple inexpensive hardware construction can be adopted. Further, since a protocol-free communication mode can be adopted, it is unnecessary to develop software to establish a protocol between the nodes, and costs can be reduced.
The multiplexing communication between the master unit and the connector units enables simplified wiring between the respective units, and thus the electrical connection test can be conducted on a compact board even if the wiring harness has a large number of circuits (e.g. having 960 contacts).
The perfect time-division multiplexing communication method, enables multiplexing communication between the respective units merely by setting the timing bit sets outputted at the specified intervals and the node addresses. Thus, the connector units can be increased and decreased easily, and changes in hardware specifications of the wiring harness can be dealt with easily.
The xe2x80x9charness-forming wirexe2x80x9d may be a terminated wire formed by connecting terminals at the opposite ends of an insulated wire or a partial harness formed by connecting a plurality of terminal-provided wires.
A connector-side connection instructing means is associated with each connector holder to indicate a connection end of the harness-forming wire. The master unit further comprises a connection assisting data storage means for storing connection assisting data for the wiring harness being produced and connection instruction control means for controlling a connection instruction by the connector-side connection instructing means via the multiplexing communication controller based on the read data and the connection assisting data.
A connected state of the harness-forming wire with the connector held in the connector holder can be read as the connection information by the master unit by conducting the multiplexing communication between the master unit and the connector unit. The connector-side connection instructing means of the connector holder connected with this connector unit can be controlled by instructing connection assistance to the connector unit in accordance with the read connection information.
The invention also is directed to a method for testing an electrical connection of a network of a wiring harness including harness-forming wires substantially every time the harness-forming wire is connected. The method preferably uses a processing system as described above and can be employed in a production line for producing the wiring harness by conveying a connection board from one to another of a plurality of stations and connecting the harness-forming wires to form the wiring harness on the connection board. The method comprises setting different node addresses for a master unit for conducting an electrical connection test for the wiring harness being produced and a plurality of connector units for connecting the master unit with the wiring harness. The method then comprises giving tokens to the respective units by a time-division technique based on timing bit sets issued at specified intervals from any of the units and the node addresses according to a perfect time-division multiplexing communication method. The method further comprises determining whether the network is satisfactory up to a final state by the perfect time-division multiplexing communication method for substantially every harness-forming wire connected in the production process of the wiring harness being tested.
The invention also is directed to a computer-readable storage medium that stores a computer program. The storage medium comprises computer-readable program means for causing a computer to control the execution of the above-described method for testing an electrical connection of a network of a wiring harness, including harness-forming wires, when the method is run on a computer. The invention also relates to a computer program and a computer program product directly loadable into the internal memory of a digital computer, comprising software code portions for performing the steps of a method for testing an electrical connection of a network of a wiring harness including harness-forming wires as described above.
The invention relates to a wire connection assisting system that preferably includes the above-described processing system. The wire connection assisting system comprises a wire supply for terminated wires formed by connecting terminals with the opposite ends of insulated wires cut to specified lengths while sorting the terminated wires beforehand according to type. The system also comprises an assembling board on which the terminated wires taken from the wire supply are to be connected. Connector holders are on the assembling board and each includes a connector accommodating portion for holding a connector to be connected with the terminated wire taken from the wire supply and a detecting element electrically connectable with a terminal of the terminated wires inserted into the connector in the connector accommodating portion. A wire-side connection instructing means is provided at the wire supply for given an instruction of taking out the wire or a specific wire in the wire supply. A connector-side connection instructing means is provided in correspondence with the respective connector holders for displaying a connection end that corresponds to the connector with which the terminated wire is to be connected. A master unit is provided on the assembling board to be at least temporarily electrically connectable with the respective detecting elements for controlling the respective connection instructing means. A wire-side node unit is at least temporarily connectable with the master unit for enabling a multiplexing communication and for driving the wire-side connection instructing means based on a control of the master unit. A connector-side node unit is at least temporarily connectable with the master unit for enabling a multiplexing communication and is adapted to control the detecting elements of the connector holders and the wire-side connection instructing means based on the control of the master unit. A multiplexing communication control system connects the master unit and the node unit as nodes to enable the multiplexing communication therebetween. The connection of harness-forming wires to form a wiring harness is assisted by controlling the respective connection instructing means based on information of a single database built in the master unit and a connection information of the harness-forming wires to be connected with the connectors on the assembling board. The multiplexing communication system further preferably comprises a node address setting means for setting different node addresses for the respective nodes, a token issuing means for issuing timing bit sets as token signals at specified intervals, and a token reception controller for giving the tokens to the respective nodes by a time-division technique based on the timing bit sets issued by the token issuing means and the node addresses.
Accordingly, a perfect time-division multiplexing communication method is adopted by providing the master unit on the assembling board and by conducting the multiplexing communication with the respective connection instructing means. The method gives tokens to the respective nodes (the master unit and the respective node units) based on the timing bit sets as the token signals issued at the specified intervals and the node addresses set for the respective nodes upon controlling the respective connection instructing means based on the information of the single database in the master unit. Thus, it is not necessary to establish communication conditions between the nodes for transmitting and receiving data, and data can be transmitted and received preferably without a protocol. This remarkably shortens response time between the nodes for transmitting and receiving the data. Thus, even if the wires are instructed to the respective connection instructing means in a complicated manner, the connection instructing means can be controlled quickly to improve operability. This enables a unitary administration of connection assisting information and electrical connection test information of a large wiring harness by the master unit using the single database, and the data can be administered and renewed more easily. Further, since the protocol-free communication mode can be adopted, it is not necessary to develop software for establishing a protocol between the nodes, and costs are reduced.
The master unit may test electrical connection of a network including the connected harness-forming wire substantially every time the harness-forming wire is connected with the connector in the connector holder. The master unit causes the respective connection instructing means to assist a next connecting operation only if there is a success in an electrical connection test. Thus, the electrical connection test is conducted every time the connecting operation is performed, and an erroneous connection can be detected by a real-time response to prevent a defective product from being conveyed to a later step. The perfect time-division multiplexing communication method remarkably shortens the time required for the electrical connection test. Thus, processing time between one set of the connecting operation and the electrical connection testing operation and the next set can be shortened, with the result that an operator needs not spend time waiting.
Wire supplies may be at each of a plurality of stations along the conveyance path of the assembling boards, and the master unit tests the electrical connection up to the last stage of the production process of the wiring harness being tested. This arrangement enables the wire connection to be instructed seamlessly from the first station to the last even if wire supplies are installed at a plurality of stations. Therefore, even if the operator is changed between the respective stations or the operation is interrupted, there is no variation in the quality of the connecting operations.
A mixed production can be made more easily by providing the master unit on the assembling board because trouble or a defect on any assembling board has no influence on the controls on the other assembling boards.
Further, the information of the single database is shared and the connecting operations are assisted at all the stations. Thus, it is not necessary to provide means for preventing a connection error of the operator by sorting the insulated wires of the products by color. As a result, the kinds of the insulated wires can be reduced and the production cost can be reduced.
The wire-side node unit may comprise a gateway for conducting a multiplexing communication with an external network. Thus, a communication line built with the master unit as a center can be connected with external networks to enable a multiplexing communication, thereby enabling various operations to be performed. For example, the data can be taught remotely to and changed in a storage means of the master unit by way of an external network. Further, the behavior of the wire connection assisting system having the master unit as a center can be monitored as it is via the external network. Hence, supplementary functions of the wire connection assisting system, such as maintenance and warnings, can be added.
The assembling board may comprise temporary holding jigs for temporarily holding the other ends of the terminated wires determined as free terminals that are to be connected when the subassembly is assembled into the wiring harness. The connector-side node unit is provided for each of the temporarily holding jigs and is connected with a terminus end instructing means for instructing the temporarily holding jig when the free terminal is brought into contact with a grounding member. The individual free terminals can be supported respectively at the suitable temporarily holding positions. As a result that the wire connecting operation can be performed efficiently.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.